Primary periodic paralysis (PP) is a group of autosomal dominant channelopathies that cause episodes of paralysis or muscle weakness that have many triggers including medication, exercise, certain foods, or stress. There is wide variation in the age of symptom onset, ranging from just after birth to late adulthood, although patients typically begin to experience attacks before age 20 years. PP affects individuals of both sexes and all races.1
The types of PP are defined by shifts in blood potassium levels during acute episodes: hypokalemic PP, the most common form of PP, involves a downward shift in serum potassium levels, whereas hyperkalemic PP is characterized by an upward shift. However, in many patients, the blood potassium levels do not fall outside the normal laboratory reference range. In Andersen-Tawil syndrome (ATS), potassium levels are inconsistent during attacks.2
“Diagnosis of PP requires a history of transient episodes of weakness, determination of ictal and steady-state serum potassium levels, [electromyogram,] and exclusion of secondary causes,” according to authors of a paper published in Brain.2 However, doctors often attribute the symptoms to other diseases or to psychological distress, and patients may not receive a diagnosis until many years after onset.
That was certainly the case for Annabelle Baughan, a retired hematologist-oncologist in France who ultimately had to investigate and determine her own diagnosis. She spoke in depth with Neurology Advisor about her disease history and frustrating encounters in the healthcare system in pursuit of a diagnosis and appropriate treatment, as well as her current status, with important advice for physicians who may encounter patients with PP.
The first part of Dr Baughan’s story is below, ending just after she was finally diagnosed. Upcoming installments will also include input from Deborah Cavel-Gréant, president of Periodic Paralysis International.